1. Field of the Invention
The present invention relates to a magnetic head slider flying above a magnetic recording medium with a small distance therebetween to record and reproduce magnetic information, and a manufacturing method therefor. Particularly, the present invention relates to a technique for improving the abrasion resistance of protrusions provided on the medium-facing surface and rails of a slider body while maintaining the manufacturing efficiency high. The present invention also relates to a technique for preventing corrosion of a magnetic head core provided on the slider body.
2. Description of the Related Art
As a conventional magnetic recording apparatus for a computer, the magnetic disk device shown in FIG. 27 is known.
This magnetic disk device comprises a magnetic head slider 82 provided above a rotatable magnetic disk 81 opposite thereto. The magnetic head slider 82 is supported by a support arm 84 through a triangular spring plate 83 so that the magnetic head slider 82 can be moved to a desired position in the diameteral direction of the magnetic disk 81 by rotation of the support arm 84 around the rotation center 84a. 
In the magnetic disk device shown in FIG. 27, with the magnetic disk 81 stopped, the bottom of the magnetic head slider 82 is lightly pressed on the magnetic disk 81 by urging force of the spring plate 83 for supporting the magnetic head slider 82, while with the magnetic disk 81 rotated, the magnetic head slider 82 flies and moves above the magnetic disk 81 at a predetermined height by means of an air flow accompanying rotation. When the rotation of the magnetic disk 81 is stopped, the flying and moving magnetic head slider 82 is again stopped by contact with the magnetic disk 81. However, in flying and moving, magnetic information is read from or written on the magnetic recording layer of the magnetic disk 81. The series of operations is generally referred to as xe2x80x9cCSS (contact start stop)xe2x80x9d.
FIGS. 28 to 30 are drawings showing the two-rail type magnetic head slider 82 conventionally used in a wide rage. FIG. 28 is a side view showing a state in which the magnetic head slider 82 flies and moves, FIG. 29 is a side view showing a static state, and FIG. 30 is an enlarged sectional view of the magnetic head slider 82 taken along the length direction of side rails 86. The magnetic head slider 82 comprises a groove (not shown) formed at the center of the bottom thereof, and the side rails 86 formed on both sides of the groove. Each of the side rails 86 has an inclined surface 86a formed on the lower side at the front end thereof (on the upstream side in the rotational direction of the magnetic disk 81) so that air flows along the inclined surfaces 86a as shown by arrows A in FIG. 28 to float and move the magnetic head slider 82 by means of the bottom of the side rails 86 of the magnetic head slider 82, which serves as a positive pressure generating portion.
A magnetic head is also known, in which as shown by a two-dot chain line in FIG. 28, a negative pressure groove 86b is formed at the bottom of the side rails 86 so that the negative pressure produced by the negative pressure groove 86b and the positive pressure produced by the side rails 86 are balanced to stabilize flying and moving performance.
Furthermore, an adhesive film 91 of Si is formed on the surface of each of the side rails 86, and a first carbon film 92 is formed on the adhesive layer 91, as shown in FIG. 30.
FIG. 28 is a side view showing a state of the magnetic head slider 82. When the magnetic head slider 82 flies and moves, air flows to the bottom side of the magnetic head slider 82 through the inclined surfaces 86a, and with the negative groove 86b formed, negative pressure is produced on the rear side of the magnetic head. Therefore, the magnetic head slider 82 flies and moves in an inclined state at a small angle in which the air inflow side is inclined upward, as shown in FIG. 28. The inclination angle is generally referred to as a xe2x80x9cpitch anglexe2x80x9d (usually about 100 xcexcRad).
The magnetic head slider 82 having the above-described construction is brought into sliding contact with the magnetic disk 81 when the magnetic disk 81 is started (rising) and stopped (falling). In order to prevent abrasion and wear of the surface of the magnetic disk, a protecting film is formed on the recording layer of the magnetic disk 81, and a lubricating layer is further formed on the protecting film.
In the magnetic head slider 82 having the above construction, from the viewpoint of magnetic recording, it is advantageous that during flying, the magnetic gap G of the magnetic head slider 82 is brought as near the magnetic recording layer of the magnetic disk 81 as possible. Therefore, in flying and moving, the height of the magnetic head slider 82 is preferably as low as possible. In recent years, the amount of flying (the spacing between the magnetic head slider 82 and the magnetic disk 81) of the magnetic head slider 82 has been further decreased with increasing recording densities and miniaturization of a magnetic disk device. In order to decrease the flying amount, the surface roughness of the magnetic disk 81 must be decreased as much as possible for avoiding contact between the magnetic head slider 82 in the flying state and the magnetic disk 81.
However, in starting or stopping the magnetic disk 81, the area of contact between the magnetic disk 81 and the magnetic head slider 82 increases as the surface of the magnetic disk 81 becomes smooth, to easily cause adhesion between the slider 82 and the magnetic disk 81. This increases adhesion torque to increase the load at the start of a motor for rotating the magnetic disk 81 and easily break the support arm 84, the magnetic head element provided on the slider or the magnetic disk recording layer at the start of rotation of the magnetic disk 81. Therefore, in order to solve this problem, protrusions 89 are provided on the air inlet side and outlet side of each of the side rails 86 through the adhesive layer and the first carbon film to decrease the area of contact with the magnetic disk 81. Each of the protrusions 89 comprises an intermediate film 93 made of Si, and a second carbon film 94 formed thereon. The first and second carbon film 92 and 94 generally comprise the same material from the viewpoint of manufacturing efficiency, etc.
An example of the manufacture of a conventional magnetic head slider having the above construction will be described below.
First, the adhesive layer 91 made of Si, the first carbon film 92, the intermediate film 93 made of Si, and the second carbon film 94 are deposited by sputtering on the medium-facing surface of a plate on the magnetic disk side thereof, which is composed of Al2O3TiC and comprises a magnetic head core 90. Then, the multilayer film comprising the adhesive layer 91, the first carbon film 92, the intermediate film 93 and the second carbon film 94 is patterned to form the side rails 86 and the groove therebetween on the medium-facing surface. The multilayer film remains on the surface of each of the side rails 86, and the surface of the plate is exposed from the groove between the side rails 86. Then, the intermediate film 93 and the second carbon film 94 on each of the side rails 86 are patterned to form the protrusion 89. As a result the magnetic head slider 82 shown in FIGS. 28 to 30.
In the conventional magnetic head slider having the above construction, in starting or stopping the magnetic disk 81, the protrusions 89 are readily worn due to friction in sliding on the magnetic disk 81, thereby causing the problem of deteriorating the effect of the protrusions 89. Therefore, as the material for the first and second carbon films 92 and 94, diamond-like carbon having good abrasion resistance is possibly used. However, the diamond-like carbon has low compactness and low degree of adhesion, and thus use as the material for the first carbon film 92 produces low corrosion resistance, causing the problem of deteriorating the magnetic core provided on the slider body.
When the surface area of the protrusions 89 on the magnetic disk side is decreased to decrease the area of contact with the magnetic disk 81, the adhesion force between the slider 82 and the magnetic disk 81 can be decreased. However, in this case, the planar pressure applied to the protrusions 89 is increased to cause the problem of increasing abrasion.
As described above, in the magnetic head slider, the height of the magnetic head slider 82 in flying and moving tends to be increased due to demand for increasing the recording density and decreasing the size of the magnetic disk device, and the pitch angle is accordingly decreased.
However, in the conventional magnetic head slider shown in FIG. 31, decreasing the pitch angle causes the protrusions 89b on the air flow outlet side (near the magnetic gap G) to project from the magnetic gap G toward the magnetic disk side during flying. In order to avoid this problem, the positions of the protrusions 89b are moved from the magnetic gap G to the air flow inlet side 82a by L1, as shown by a broken line in FIG. 31.
However, where the positions of the protrusions 89a are moved to the air flow inlet side 82a, at a stop of the magnetic disk 81, the portion (near the magnetic gap G) of the medium-facing surface of the magnetic head slider 82, where no protrusion is provided, adheres to the magnetic disk 81 due to a liquid lubricant film coated on the surface of the magnetic disk 81 to cause the problem of increasing adhesion torque.
The present invention has been achieved in consideration of the above situation, and a first object of the present invention is to provide a magnetic head slider in which the abrasion resistance of protrusions provided on the medium-facing surface and rails of the slider body can be improved, and corrosion of a magnetic head core provided on the slider body can be improved.
A second object of the present invention is to provide a magnetic head slider in which the abrasion resistance of protrusions provided on rails the slider can be improved to prevent an increase in adhesion force between the slider and a magnetic disk.
A third object of the present invention is to provide a magnetic head slider in which can further decrease adhesion between a magnetic disk and the slider body comprising protrusions provided on the medium-facing surface and rails on the magnetic disk side.
In order to achieve the objects, in accordance with a first aspect of the present invention, there is provided a magnetic head slider comprising a magnetic head core provided in a plate-shaped slider body, and rails formed on the medium-facing surface of the slider body on the magnetic disk side, for generating flying force so that the slider flies and moves above a magnetic disk to write or read magnetic information, wherein a first carbon film having corrosion resistance is provided on at least the surfaces of the rails among the medium-facing surface and the rails of the slider body through an adhesive layer, protrusions formed by alternately laminating an intermediate film and a second carbon film are provided on the first carbon film, and at least the outermost second carbon film of the second carbon films, which constitute each of the protrusions, has abrasion resistance.
In the magnetic head slider having the above construction, the second carbon film having abrasion resistance is formed on the outermost surface of each of the protrusions to prevent abrasion of the protrusions during sliding on the magnetic disk when the magnetic disk is stared and stopped, thereby significantly improving the abrasion resistance of the protrusions. Furthermore, at least the surfaces of the rails among the medium-facing surface and the rails of the slider body are coated with the first carbon film having corrosion resistance to prevent corrosive deterioration of the magnetic head core provided in the slider body.
As described above, since the abrasion resistance of the protrusions is significantly improved, an increase in the area of contact between the slider and the magnetic disk can be prevented. Therefore, it is possible to prevent the magnetic head element provided on the magnetic head core, and the recording layer of the magnetic disk from being damaged due to an increase in adhesion force between the slider and the magnetic disk at a start of rotation of the magnetic disk.
Furthermore, in forming the first and second carbon films having the above-described properties by an ECRCVD (Electron Cyclotron Resonance Chemical Vapor Deposition) method, the carbon films having different properties can be efficiently produced by changing the types of reaction gases (gases containing carbon) supplied into a deposition apparatus, and controlling a substrate bias.
Therefore, in the magnetic head slider of the present invention, the abrasion resistance of the protrusions provided on the medium-facing surface and the rails of the slider body can be improved while the manufacturing efficiency kept high, and corrosion of the magnetic head core provided in the slider body can be prevented.
In the magnetic head slider of the present invention, the first carbon film having corrosion resistance preferably comprises a carbon film having a hydrogen content of 30 atomic % or more, and the second carbon film having abrasion resistance preferably comprises a carbon film having a film hardness of 22 GPa or more.
For example, in forming, by the ECRCVD method, the first carbon film having a hydrogen content of 30 atomic % or more on the intermediate film of the slider body, on which the adhesive layer, the first carbon film and the intermediate film are formed, the first carbon film can be deposited by changing the type of reaction gas (gas containing carbon) supplied into the deposition apparatus, and controlling the substrate bias (decreasing the substrate bias). By using methane gas as the reaction gas, the carbon film having a hydrogen content of 35 atomic % or more can be deposited. By using ethylene gas as the reaction gas, the carbon film having a hydrogen content of over 30 atomic % can be deposited by controlling the substrate bias.
In this way, the hydrogen content of the first carbon film formed to cover the surfaces of at least the rails among the medium-facing surface and the rails of the slider body is increased to decrease film hardness. However, the degree of compactness is increased due to the formation of an amorphous phase to increase the degree of adhesion, thereby preventing peeling. Therefore, the magnetic head core provided in the slider body can be prevented from deteriorating due to corrosion.
For example, in forming, by the ECRCVD method, the second carbon film having a film hardness of 22 GPa or more on the intermediate film of the slider body, on which the adhesive layer, the first carbon film and the intermediate film are formed, the second carbon film can be deposited by changing the type of the reaction gas (gas containing carbon) supplied into the deposition apparatus and controlling the substrate bias (increasing the substrate bias) so that the hydrogen content of the carbon film is decreased.
The hydrogen content of the second carbon film is preferably less than 30 atomic %.
In this way, the hydrogen content of the second carbon film which constitutes each of the protrusions is decreased to strengthen carbon atom bonding, and increase the hardness.
Also, the second carbon film may comprise a carbon film having a hydrogen content of 0 atomic %. Example of such a carbon film comprises cathodic arc carbon (CAC). The second carbon film comprising cathodic arc carbon can be deposited by, for example, arc discharge of a graphite block in a vacuum atmosphere in the deposition apparatus in which the slider body, on which the adhesive layer, the first carbon film and the intermediate film are formed, is arranged.
Furthermore, the magnetic head core of the magnetic head slider of the present invention preferably comprises a giant magnetoresistive element.
The method of manufacturing the magnetic head slider according to the first aspect of the present invention comprises the step of forming the adhesive layer and the first carbon film having corrosion resistance on the medium-facing surface on the magnetic disk side of the plate-shaped slider body comprising the magnetic core, the step of alternately forming the intermediate film and the second carbon film on the first carbon film so that the outermost second carbon film has abrasion resistance, and the step of patterning at least the outermost second carbon film and the intermediate film located below the outermost film in the multilayer film comprising the adhesive layer, the first carbon film, the intermediate film and the second carbon film to form protrusions.
The method of manufacturing the magnetic head slider having the above construction can be suitably used for manufacturing the magnetic head slider of the present invention.
In the method of manufacturing the magnetic head slider of the present invention having the above construction, the first carbon film having corrosion resistance preferably comprises a carbon film having a hydrogen content of 30 atomic % or more, and the second carbon film having abrasion resistance preferably comprises a carbon film having a film hardness of 22 GPa or more.
In accordance with a second aspect of the present invention, there is provided a magnetic head slider comprising a magnetic head core provided in a plate-shaped slider body so that the slider flies and moves above a magnetic disk to write or read magnetic information, wherein a rail and/or pad is formed for producing buoyant force on the medium-facing surface on the magnetic disk side of the slider body, and a protrusion having a film hardness of 22 GPa or more is formed on the rail and/or pad.
In the magnetic head slider having the above construction, the protrusion provided on the rail and/or pad has a film hardness of 22 GPa or more so that the abrasion resistance of the protrusion can be significantly improved to prevent wear of the protrusion in sliding on the magnetic disk at the time of start or stop of the magnetic disk, thereby preventing an increase in the area of contact between the slider and the magnetic disk, and an increase in adhesion force therebetween. Therefore, the magnetic head element provided on the magnetic head core and the recording layer of the magnetic disk can be prevented from being damaged due to an increase in the adhesion force between the slider and the magnetic disk when rotation of magnetic disk is started.
In the magnetic head slider of the present invention having the above construction, the protrusion preferably comprises a carbon film having a hydrogen content of less than 43 atomic %. In forming such a carbon film on the medium-facing surface on the magnetic disk side of the slider body, for example, by the ECRCVD (Electronic Cyclotron Resonance Chemical Vapor Deposition) method, the carbon film can be produced by changing the type of the reaction gas (gas containing carbon) supplied into the deposition apparatus and controlling the substrate bias.
The protrusion may comprise a carbon film having a hydrogen content of 0 atomic %. An example of such a carbon film comprises cathodic arc carbon (CAC).
By decreasing the hydrogen content of the carbon film which constitutes the protrusion, bonding of carbon atoms can be strengthened to increase hardness.
In the magnetic head slider of the present invention having the above construction, the rail and/or pad may comprise side rails and/or pads which are formed on both marginal sides of the medium-facing surface on the magnetic disk side of the slider body to extend from the air flow inlet side to the air flow outlet side of the slider body, and the protrusion having a hardness of 22 GPa or more may be formed on the air flow inlet side and the air flow outlet side of the side rail and/or pad.
In the magnetic head slider of the present invention having the above construction, the rail and/or pad may comprise side rails which are formed on both marginal sides of the medium-facing surface on the magnetic disk side of the slider body to extend from the air flow inlet side to the air flow outlet side of the slider body, and a center rail formed between the side rails, and the protrusion having a hardness of 22 GPa or more may be formed at least on the air flow inlet side of the side rails.
The magnetic head slider of the present invention having the above construction may comprise a plurality of the rails and/or pads which are provided in the direction from the air flow inlet side to the air flow outlet side of the slider body.
In the magnetic head slider of the present invention having the above construction, the rail preferably comprises a crown which is formed thereon so that a magnetic gap provided on the slider body can be brought nearer to the magnetic disk.
In the magnetic head slider of the present invention having the above construction, the magnetic head core preferably comprises a giant magnetoresistive element.
In accordance with a third aspect of the present invention, there is provided a magnetic head slider comprising a magnetic head core provided in a plate-shaped slider body, and a rail formed on the medium-facing surface on the magnetic disk side of the slider body, for producing buoyant force so that the slider flies and moves above a magnetic disk to write or read magnetic information, wherein a plurality of protrusions are provided on at least the rail among the medium-facing surface and the rail of the slider body along the length direction of the slider body, and one of the plurality of protrusions, which is nearest to the magnetic head core, is lower than the other protrusions.
In the magnetic head slider of the present invention having the above construction, the protrusion lower than the other protrusions is interposed between the medium-facing surface of the slider body and the magnetic disk in the portion near the magnetic head core side (the air flow outlet side) when the magnetic disk is stopped. Therefore, a meniscus of a lubricant coated on the surface of the magnetic disk has a large radius around the lower protrusion to prevent adhesion of the medium-facing surface of the slider body to the magnetic disk due to the liquid film of the lubricant, thereby improving the effect of decreasing adhesion between the slider body and the magnetic disk. Since the protrusion nearest to the magnetic head core is lower than the other protrusions so that the protrusion nearest to the magnetic head core can be prevented from projecting from the magnetic gap to the magnetic disk side during flying of the magnetic head slider at a pitch angle of about 100 xcexcRad. Namely, it is advantageous that the magnetic gap can be brought nearer to the magnetic disk than the plurality of the protrusions.
In the magnetic head slider of the present invention having the above construction, the heights of the plurality of the protrusions may be gradually decreased in the direction from the air flow inlet side to the air flow outlet side of the slider body.
In the magnetic head slider of the present invention having the above construction, the rail may comprise side rails which are formed on both marginal sides of the medium-facing surface on the magnetic disk side of the slider body to extent from the air flow inlet side to the air flow outlet side of the slider body, and the plurality of the protrusions may be provided along the length direction of each the side rail.
The magnetic head slider of the present invention having the above construction may further comprise a groove provided between the side rails of the slider body so that the plurality of the protrusions may be provided on each of the side rails and in the groove.
In the magnetic head slider of the present invention having the above construction, the end (lower end) of at least the protrusion of the plurality of the protrusions, which is nearest to the magnetic head core, is preferably higher than the magnetic gap of the magnetic head core. Namely, the distance between the magnetic disk and the end of at least the protrusion of the plurality of the protrusions, which is nearest to the magnetic head core, is preferably larger than the distance between the magnetic gap of the magnetic head core and the magnetic disk.
In the magnetic head slider having the above construction, in flying of the magnetic head slider, the magnetic gap can be advantageously brought nearer to the magnetic disk than the plurality of the protrusions, and contact between the ends of the protrusions and the magnetic disk can be prevented.
In the magnetic head slider of the present invention having the above construction, in the flying state of the magnetic head slider, the protrusion nearest to the magnetic head core preferably does not project to the magnetic disk side from the line connecting the other protrusions and the magnetic gap of the magnetic head core.
In the magnetic head slider having the above construction, in flying of the magnetic head slider, the magnetic gap can be advantageously brought nearer to the magnetic disk than the plurality of the protrusions, and contact between the ends of the protrusions and the magnetic disk can be prevented.
In the magnetic head slider of the present invention having the above construction, the distance between the magnetic gap and the protrusion nearest to the magnetic head core is preferably 25% or less of the length of the slider body.
In the magnetic head slider having the above construction, the lower protrusion is interposed between the medium-facing surface of the slider body and the magnetic disk in the portion near the magnetic gap when the magnetic disk is stopped, and the distance between the protrusion and the magnetic gap is small. Therefore, the effect of preventing adhesion of the medium-facing surface of the slider body to the magnetic disk due to the liquid film of the lubricant can be improved to exhibit the excellent effect of preventing adhesion between the slider body and the magnetic disk.
In the magnetic head slider of the present invention having the above construction, at least the outermost layer of each of the protrusions preferably comprises a carbon film having a film hardness of 22 GPa or more to improve the abrasion resistance of the protrusions, and prevent wear of the protrusions during sliding on the magnetic disk when the magnetic disk is started and stopped.
In the magnetic head slider of the present invention having the above construction, the magnetic head core preferably comprises a giant magnetoresistive element.
The method of manufacturing the magnetic head slider according to the third aspect of the present invention comprises alternately laminating an intermediate film and a carbon film on the medium-facing surface on the magnetic disk side of the plate-shaped slider body comprising the magnetic head core to form a multilayer film, and patterning the multilayer film to form a plurality of protrusions, wherein of the plurality of protrusions, the protrusion nearest to the magnetic head core is lower than the other protrusions.
The method of manufacturing the magnetic head slider having the above construction can be preferably used for manufacturing the magnetic head slider of the present invention.